tetraproc: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/tetraproc - from package: tetraproc

You may install the required package with command apt-get install {package}

Error in other languages:
tetraproc: bevel nie gevind nie
tetraproc: comandă negăsită
tetraproc: comando não encontrado
tetraproc: commande introuvable
tetraproc: command not found
tetraproc: käsku ei ole
tetraproc: không tìm thấy lệnh
tetraproc: komanda nerasta
tetraproc: Kommando nicht gefunden.
tetraproc: kommandot finns inte
tetraproc: komut yok
tetraproc: nie znaleziono polecenia
tetraproc: níor aimsíodh an t-ordú
tetraproc: no se encontró la orden
tetraproc: no s'ha trobat l'ordre
tetraproc: opdracht niet gevonden
tetraproc: parancs nem található
tetraproc: perintah tidak ditemukan
tetraproc: príkaz nenájdený
tetraproc: příkaz nenalezen
tetraproc: команда не найдена
tetraproc: командата не е открита
tetraproc: 命令找不到
tetraproc: コマンドが見つかりません